Effects of exercise, dietary cholesterol, and dietary fat on blood lipids.
Exercise, a low fat diet, or a diet low in saturated fat content can each lower plasma total cholesterol and low-density lipoprotein (LDL) cholesterol. We investigated whether these factors together could prevent the lipid-raising effects of dietary cholesterol. Ten healthy, athletic, normolipidemic male volunteers were studied. Two diets of 4 weeks duration each were compared in a randomized, blind crossover design. Diets were identical except for cholesterol content: one contained 600 mg/d; the other 200 mg/d. Both diets contained 15% of calories as protein, 55% as carbohydrate, 30% as fat, and the polyunsaturated fat to saturated fat ratio was 1.5. Exercise level and body weight were kept constant in each subject. As compared with plasma values obtained following the 200-mg/d cholesterol diet, mean values following the 600-mg/d cholesterol diet significantly increased for LDL cholesterol and apolipoprotein B by 10% and 13%, respectively. Mean plasma triglycerides, high-density lipoprotein 2 and 3, and apolipoprotein A-1 levels did not change significantly. Individual responses, however, were highly variable. Three subjects increased LDL cholesterol by more than 25%; 2 subjects increased LDL cholesterol by 10% to 25%; and 5 subjects had 5% or less change in LDL cholesterol. A dietary cholesterol increase can significantly elevate plasma LDL cholesterol and apolipoprotein B in certain normolipidemic, healthy men even when they are exercising regularly and consuming a moderately fat restricted, low saturated fat diet. Dietary cholesterol restriction may therefore be justifiable even when other life-style and dietary measures to minimize blood cholesterol are undertaken.
Johnson
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C
Department of Medicine, University of Rochester, School of Medicine and Dentistry, NY.
Greenland
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P
D000328:Adult; D001053:Apolipoproteins / Q000097:blood; D002791:Cholesterol, Dietary / Q000008:administration & dosage*; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D004041:Dietary Fats / Q000008:administration & dosage*; D015444:Exercise; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D011897:Random Allocation
D001053:Apolipoproteins; D002791:Cholesterol, Dietary; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004041:Dietary Fats; D008055:Lipids